This invention relates generally to compositions and methods for the treatment and nutritional support of patients. More specifically, this invention relates to the nutritional support of obese patients prior to, during and after hospitalisation for surgery, treatment of diseases or other disorders as well as during periods of convalescence.
The prevalence of obesity in adults, children and adolescents has increased rapidly over the past 30 years in the United States and globally and continues to rise. Obesity is classically defined based on the percentage of body fat or, more recently, the body mass index or BMI. The BMI is defined as the ratio of weight in Kg divided by the height in meters, squared. As obesity becomes more prevalent in all age groups, it is inevitable that the number of patients in hospitals who are also obese will increase.
Many obese patients have pre-existing chronic diseases related to their obesity such as impaired glycaemic control, diabetes mellitus, coronary artery disease, hypertension, respiratory abnormalities, hyperlipidaemia, degenerative joint disease, and hepatobiliary disease that are likely to complicate even routine hospital care. In addition, obese patients are more likely than their non-obese counterparts to develop postoperative complications such as impaired wound-healing, nosocomial infections, respiratory complications, and delayed cardiac recuperation. In adult intensive care patients, obesity (BMI greater than 30) has even been reported to be significantly associated with increased risk of mortality. Obesity entails increased oxidative stress and, in many cases, sarcopenia. It is well known that acute illness and/or surgical intervention is also associated with oxidative stress as well as negative nitrogen balance and loss of muscle mass, and in many cases insulin resistance is enhanced. In other words, acute illness is likely to exacerbate physiological and metabolic alterations already present at baseline in obese patients.
Recently, Dickerson et al (Nutrition 18:241-246 2002) compared the effects of hypocaloric and eucaloric enteral tube feeding in critically ill obese patients. Their results suggested that hypocaloric enteral nutritional support (by which the authors meant feeding a composition with an energy density of at least 1.0 kcal/ml) was at least as effective as eucaloric feeding in this group. In the more generalised group of obese patients who, although ill, are not critically ill, there is a tendency for the nutrition offered post operatively in particular to be less than ideal. These patients tend to be offered either the same feeds as non-obese patients and thus ingest calories they do not require. Alternatively, it is assumed that in the short term no nutritional support at all is needed because the patients are calorically abundant. However, this overlooks the possibility that, when stressed for example by illness or surgery, obese patients may suffer from protein and micronutrient depletion just as non-obese patients do. Further, as noted above, obese patients are at greater risk of postoperative complications and would be in better conditions to resist these complications if they were not further weakened by impaired nutritional status. A need therefore exists for a nutritional composition designed to meet the nutritional needs of patients who are obese.